Battery and assembly method thereof

ABSTRACT

A battery includes a plurality of electrode members each having a positive electrode, a negative electrode and an insulating separator arranged between the positive electrode and the negative electrode, bus bars each electrically connected to electrode members, and a battery case that houses the electrode members.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2012-066062, filed Mar. 22, 2012; theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate to a battery and a manufacturingmethod thereof.

BACKGROUND

In recent years, rechargeable batteries have been widely used as powersources in electric cars, hybrid electric cars, power-assisted bicycles,and electric equipment. For instance, lithium ion rechargeablebatteries, which are non-aqueous rechargeable batteries, have been usedas a power source in electric cars because they have high output andhigh energy density.

A rechargeable battery is typically composed of an outer container madeof aluminum (or similar metal) that is in the form of flat rectangularbox. The battery has an electrode group housed together with anelectrolytic solution in the outer container and electrode terminals,which are connected to the electrode group and set in the outercontainer.

In addition, in order to attain high capacity and high output, arechargeable battery may consist of a plurality of cells arranged in acase or box. The plurality of cells may be connected in parallel or in aseries to create a battery set. The terminals of the individual cellsmay be attached to bus bars or electric circuits that connect cellsadjacent to the outer surface of the battery set.

In the battery set, the processes of assembling the plurality of cellsand electrically connecting plural leads, terminals and bus bars arecomplicated.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the external appearance of arechargeable battery device according to an embodiment.

FIG. 2 is a perspective view showing the internal structure of therechargeable battery device.

FIG. 3 is a perspective view showing the composition of electrode groupof the rechargeable battery device.

FIG. 4 is a perspective view showing the upper side of bus bar of therechargeable battery device.

FIG. 5 is a perspective view showing the bottom side of bus bar of therechargeable battery device.

FIG. 6 is a cross-sectional view showing the connection structure of therechargeable battery device.

FIG. 7 is a perspective view showing part of the assembling process ofthe rechargeable battery.

DETAILED DESCRIPTION

In general, according to one embodiment, a rechargeable battery deviceaccording to an embodiment will be explained by referring to FIG. 1 toFIG. 7. In each figure, direction arrows X, Y, and Z show three mutuallyorthogonal directions. Furthermore, in each diagram, appropriate partsof the rechargeable battery is expanded, reduced or omitted for purposeof illustration.

A battery according to one embodiment includes a plurality of electrodemembers having a positive electrode plate, a negative electrode plate,and an insulating separator placed between the positive electrode plateand the negative electrode plate, a first case made of resin, in which aplurality of leads connected electrically to each of the plurality ofelectrode members and bus bars having a plurality of terminals to beconnected electrically to each of the plural leads are integrated, and abattery case housing the plural electrode members therein.

FIG. 1 is a perspective view showing the external appearance of arechargeable battery device 1 according to an embodiment, and FIG. 2 isa perspective view showing its internal structure. The rechargeablebattery device 1 shown in FIG. 1 and FIG. 2 is composed of a batterycase 11 with a housing part 11 a (see FIG. 7) which is a space formed bydividing the inner part of the battery case 11 in plural numbers, pluralelectrode groups 12 housed together with a non-aqueous electrolyticsolution in the battery case 11, and a battery set that is made up ofplural rechargeable battery units, each of which functions as arechargeable battery.

Furthermore, in the embodiment, each of the electrode groups 12 iscomposed of electrode members including a positive electrode plate, anegative electrode plate, an insulating separator placed therebetween,and leads which are connected electrically to each of the positiveelectrode plate and the negative electrode plate (for example, positiveelectrode lead 22 a and negative electrode 22 b in FIG. 3).

The battery case 11 has a first case 13 and a second case 14, and has arectangular box form. The first case 13 and the second case 14 aresealed to form a sealed space in the battery case 11, in which anon-aqueous electrolytic solution and plural electrode groups 12 arehoused.

As resin materials to be used in the first case 13 and the second case14, thermoplastic resins (non-crystalline) are preferred, for example,modified PPE (polyphenylene ether).

The first case 13 has a “basket” form, and many partitioning plates areplaced therein. More specifically, the first case 13 is equipped with anouter part (basket body) 13 a, which has a bottom-opened rectangular boxform, and plural partitioning plates 13 b, which are arranged inparallel within the outer part 13 a. The outer part 13 a has a ceilingwall 13 c, which covers one side of the electrode group 12, and sidewalls 13 d, which cover the circumference, and has an opening at thebottom side. In the ceiling wall 13 c, plural bus bars 15 are integratedtherein by insert molding. The outer part 13 a carries out a function ofpreventing short-circuit between terminals by electrical insulation

A substrate housing part 13 e is formed on the outer surface side of theceiling part 13 d, on which a circuit substrate 17 for voltage detectionis arranged. The substrate housing part 13 e has a concavity at itsupper side with a fixed width along the longitudinal direction (Xdirection) in the central part of the battery case 11.

In the substrate housing part 13 e, voltage detection terminals 15 dbeing constituted as a part of bus bar 15 and outer output terminal 16,which is connected individually to positive electrode lead 22 a of theelectrode group 12 at one end of the array and negative electrode lead22 b of the electrode group 12 at the other end of the array, areexposed to the outer side of the first case 13.

The partition plates 13 b are arranged in parallel so as to partitionthe inner space of the outer part 13 a a plural number of times in the Xdirection and to form in parallel plural housing compartments 11 a (seeFIG. 7) each having a form corresponding to the shape of the electrodegroup 12. In the embodiment, 11 units of partition plates 13 b areformed in parallel along the X direction, and 12 units of housingcompartment 11 a are formed in parallel in the X direction. Thepartition plate 13 b carries out a position-locating function ofelectrode group 12 and prevents short-circuit between the electrodegroups 12.

Each of the housing compartments 11 a has a narrow and long rectangularshape corresponding to the shape of the electrode group 12 housedtherein. Each electrode group 12 is housed to extend along the widthdirection (Y direction) of the battery case 11 so that plural electrodegroups 12 are arranged in parallel along the longitudinal direction (Xdirection) of the battery case 11.

In the ceiling wall 13 c, plural bus bars 15 and exterior outputterminals 16 are integrally molded by inserting molding. Here, 11 unitsof bus bars 15 are arranged in parallel at a predetermined position soas to connect serially adjacent 12 units of electrodes in the electrodegroups 12, and exterior output terminals 16 are arranged at both ends ofthe array. In such a manner, plural bus bars 15 and exterior outputterminals 16 are formed integrally in the first case 13. One part ofplural bus bars 15 and exterior output terminals 16 is exposed to theoutside of the first case 13, and another part thereof is within thefirst case 13.

Besides, in the ceiling wall 13 c, gas-discharging valves orliquid-injecting holes are formed. When gas is generated inside the caseby abnormal operation and the like, and the internal pressure risesabove the predetermined value, gas is released through the valves. Thislowers the internal pressure and prevents failure such as rupture andthe like.

In the present embodiment, as mentioned above, each electrode group 12is composed of electrode members each having a positive electrode plate,a negative electrode plate and an insulating separator formedtherebetween, and leads for electrically connecting each positiveelectrode plate and negative electrode plate of the electrode member. Asshown in FIG. 3 as an example, the composition of electrode group 12refers to the positive electrode lead 22 a and negative electrode lead22 b. As shown in FIG. 3, the electrode group 12 is provided with coil21 obtained by winding the positive electrode plate and the negativeelectrode plate and making them into a flat shape, positive electrodelead 22 a and negative electrode lead 22 b which are pulled out at bothsides of the coil 21.

The coil 21 is formed by winding spirally a positive electrode plate, anegative electrode plate, and an insulating separator placedthere-between and compressing along the diameter direction to make itinto a rectangular flat form.

The positive electrode lead 22 a and negative electrode lead 22 b areextended toward an upper part higher than the coil 21 to have a plateform that is bent toward the inner side. A cap 24 is formed between thepositive electrode lead 22 a and the negative electrode lead 22 b. Thecap 24 is formed from insulating resin and the like in a plate form, andit is formed by inserting it between positive electrode lead 22 a andnegative electrode lead 22 b so that the distance between the positiveelectrode lead 22 a and the negative electrode lead 22 b is regulated tocontrol the positions of the positive electrode lead 22 a and thenegative electrode lead 22 b. By the control function of the cap 24, apair of positive electrode leads 22 a and negative electrode lead 22 bcan be connected with high accuracy to their respective terminals, 15 aand 15 b.

Positive electrode connector 23 a and negative electrode connector 23 bare inserted into holes 15 e of bus bar 15 to connect the terminal 15 aand the terminal 15 b respectively to the positive electrode lead 22 aand negative electrode lead 22 b.

Plural electrode groups 12 are arranged so as to stand alternate betweenpositive electrode connector 23 a and negative electrode connector 23 bof adjoining electrode groups 12. Plural electrode groups 12 areelectrically connected serially by plural bus bars 15 as conductivematerial.

Exterior output terminals 16 are connected respectively to the negativeelectrode connector 23 b of the electrode group 12 positioned at one endof the array among plural electrode groups 12 and the positive electrodeconnector 23 a of the electrode groups 12 positioned at the other end ofthe array.

Each of plural bus bars 15, shown in FIG. 1, FIG. 2, FIG. 4, and FIG. 5,is made from conductive materials such as metallic materials, e.g.aluminum, copper, bronze and the like, and includes the terminals 15 a,15 b, connection plate 15 c for connecting them, and the voltagedetection terminal 15 d as one integrated single body.

Here, bus bar 15 has a T-shape, and has a pair of cylindrical terminals15 a, 15 b connected to each other integrally, and a part of the middleof terminals 15 a, 15 b extended towards the central part in the widthdirection (arrow direction Y) to function as a voltage detectionterminal 15 d.

The terminal 15 a at one side is connected to positive electrodeconnector 23 a of an electrode group 12 while the terminal 15 b at theother side is connected to negative electrode connector 23 b of anadjacent electrode group 12, and those electrode terminals are connectedelectrically. Twelve units of electrode group 12 are connected seriallyby plural bus bars 15 in the same manner as described above.Alternatively, plural electrode groups 12 may be connected in parallel.

Each of the terminals 15 a, 15 b is composed of, for example, the formof cylinder having a bottom, and a hole 15 e, which extends in the Zdirection, is formed at the center of the bottom.

One end of terminals 15 a, 15 b is projected to the inner side ofceiling 13 a of the first case 13. The terminals 15 a, 15 b are joinedto the first case 13 by insert molding and buried therein as anintegrated member. The voltage detection terminal 15 d is exposed to theoutside from the concave part 13 e of the first case 13.

Each of the terminals 15 a and 15 b of bus bar 15 is arranged tocorrespond to each of positive electrode lead 22 a and negativeelectrode lead 22 b, and each electrode group 12 is located in acorresponding housing compartment 11 a of the first case 13, whilepositive electrode connector 23 a and negative electrode connector 23 b,which correspond to positive electrode lead 22 a and negative electrodelead 22 b of electrode group 12, respectively, are inserted into holes15 e of the terminals 15 a and 15 b.

With the configuration described above, positive electrode connector 23a and negative electrode connector 23 b of adjacent electrode groups 12are electrically connected to each other through connector 15 c andterminal 15 a, 15 a of bus bar 15.

Exterior output terminal 16 has a terminal 16 a or 16 b composed ofcylindrical part with a hollow insertion part (hole) at the bottomthereof and a plate-form voltage detection terminal 16 c, which extendsfrom a center portion of the terminal 16 a or 16 b, and they are formedintegrally as one body from conductive materials such as metallicmaterials, e.g., aluminum, copper, bronze, gold and the like.

The terminal 16 a or 16 b of the exterior output terminal 16 is arrangedto correspond to negative electrode connector 23 b of electrode group 12positioned at one end of the array of electrode groups 12 and positiveelectrode connector 23 a of electrode group 12 positioned at the otherend of the array. The position of electrode group 12 is determined inhousing compartment 11 a of the first case 13 while positive electrodeconnector 23 a and negative electrode connector 23 b are inserted,respectively, into the holes of the terminal 16 a or 16 b.

A circuit board 17, which includes a voltage control unit, a voltagedetection unit, and a temperature sensor or the like, is formed in thesubstrate housing part 13 e that is at the outer surface side of thefirst case 13, and connected electrically to the voltage detectionterminal 15 b, 16 c exposed to the outside of substrate housing part 13e.

The second case 14 is provided with plate-form bottom wall 14 a closingup the bottom opening of the first case 13.

The top surface of bottom wall 14 a is provided with curved surfaces,which are curved along the shape of electrode group 12 and arranged inparallel. After housing the electrode group 12, the second case 14 isassembled to the first case 13 in a manner of closing up the bottomopening so that the housing compartment 11 a is closed up.

Hereinafter, the method of assembling batteries according the presentembodiment is explained by referring to FIG. 6 and FIG. 7. In terms ofthe assembling process, as shown in FIG. 6 and FIG. 7, first, electrodegroup 12 is arranged in the first case 13 by inserting individualelectrode group 12 into each housing compartment 11 a of the first case13 through the bottom opening.

As described above, the first case 13 is a resin molded article and hasa basket form. In the first case 13, each of the electrode groups 12 isarranged in the compartment 11 a of the battery case 11 so that positiveelectrode connector 23 a and negative electrode connector 23 bcorresponding to positive electrode lead 22 a and negative electrodelead 22 b of adjacent electrode groups 12, respectively, are insertedinto respective holes 15 e of the terminals 15 a and 15 b that areconnected by connection part 15 c. In the first case 13, positiveelectrode connector 23 a and negative electrode connector 23 b, whichare connected to positive electrode lead 22 a and negative electrodelead 22 b, respectively, are electrically connected by bus bar 15.Furthermore, positive electrode connector 23 a and negative electrodeconnector 23 b of electrode group 12 at both ends of array are insertedinto respective hole of exterior output terminals 16 and joined byelectrical connection and physical joining.

As shown in FIG. 7, the second case 14 is assembled at the arrangedstate of all electrode groups 12 so as to close up the bottom opening ofthe first case 13. Thus, electrode group 12 is housed in compartment 11a and sealed.

Then, circuit board 17 is arranged in substrate housing part 13 e so asto connect to voltage detection terminals 15 d, 16 c which are exposedto the outer surface of the first case 13.

Furthermore, various treatments such as electrolytic solution treatment,initial charging and discharging, and the like are carried out in orderto complete the rechargeable battery device 10 as a battery set.

The following effect is achieved by the rechargeable battery device andthe method of assembling a rechargeable battery device according to thisembodiment. Namely, since bus bar 15 is integrated into the resin-madebattery case 11, the assembling process can be simplified and also theproblems in the installation process of bus bar 15 can be reduced sothat the loss of product yield can be reduced.

Electrode group 12 with coil 21, positive electrode lead 22 a, andnegative electrode lead 22 b is arranged in the compartment 11 a in thebattery case 11, positive electrode connector 23 a and negativeelectrode connector 23 b, which correspond to positive electrode lead 22a and negative electrode lead 22 b of the electrode group 12,respectively, are inserted into a hole 15 e of bus bar 15 simultaneouslyat the time of assembling of battery case 11. Therefore, number ofassembling parts can be reduced and assembling process can be simplifiedwith preservation of high accuracy.

Furthermore, in the embodiment, a case of arranging plural electrodegroups 12, for example, in a row and connecting them electrically inseries is explained, but the present invention is not limited to this.The present invention can be applied to cases where the plural electrodegroups 12 are connected in parallel. Even in such cases, electricalconnection of leads and bus bars can be easily carried out during theassembling of electrode groups into the case since bus bars areintegrated in the resin-made case.

In the embodiment, partition plate 13 b is integrated at the side of thefirst case 13 and plural housing compartments 11 a are produced, but itis limited to this case only. For example, it can be composed byseparating the ceiling 13 a and the side part 13 c and making a thirdcase with side part 13 c and partition plate 13 b as a separatestructure. Even such a case, bus bar 15 is insert-molded integrally inceiling 13 a so that same effect of the embodiment is obtained.

Various materials besides the modified PPE can be used as resins for thefirst case 13 and the second case 14. For example, olefin resins such asPE, PP, PMP and the like, polyester resins such as PET, PBT, PEN and thelike, POM resin, polyamide resins such as PA6, PA66, PA12 and the like,crystalline resins such as PPS resin, LCP resin and the like, and theiralloy resins, non-crystalline resins such as PS, PC, PC/ABS, ABS, AS,PES, PEI, PSF and the like, and their alloy resin can be used. Inaddition, positive electrode material and negative electrode material ofcoil 21, and materials for terminal 15 can be modified according to theaforementioned materials.

While certain embodiments have been described, these embodiments havebeen presented as examples only, and are not intended to limit the scopeof the inventions. In fact, the novel embodiments described herein maybeembodied in a variety of other forms; furthermore, various omissions,substitutions and changes of the embodiments described herein can bemade without departing from the spirit of the inventions. The claimsdescribed below and their equivalents are intended to cover such formsor modifications as would fall within the scope and spirit of theinventions.

What is claimed is:
 1. A battery comprising: a plurality of electrodemembers each including a positive electrode, a negative electrode and aninsulating separator arranged between the positive electrode and thenegative electrode; a plurality of bus bars each electrically connectingelectrode members; and a battery case in which the plurality ofelectrode members are housed, the battery case including a portion madeof resin in which the bus bars are arranged at predetermined positionsrelative to each other.
 2. The battery according to claim 1, whereineach of the bus bars has terminals formed thereon, and connectorsprojecting from each of the positive and negative electrodes are eachelectrically connected to one of the terminals.
 3. The battery accordingto claim 2, wherein the terminals each have a hole formed therein intowhich a corresponding connector is inserted.
 4. The battery according toclaim 2, wherein each of the bus bars has a connector section extendingbetween the terminals, and the connector section electrically connects apositive terminal electrically connected to one of the adjacentelectrode members to a negative terminal electrically connected to adifferent one of the adjacent electrode members.
 5. The batteryaccording to claim 4, wherein each of the bus bars includes a voltagedetection terminal that is electrically connected between the terminalsthereof.
 6. The battery according to claim 1, wherein the bus bars areintegrated into the portion by molding.
 7. The battery according toclaim 6, wherein the voltage detection terminal is exposed to anexterior of the battery case.
 8. The battery according to claim 7,wherein the battery case has a recessed portion and the voltagedetection terminals are exposed through the recessed portion.
 9. Thebattery according to claim 1, wherein the battery case includes apartition plate to form a plurality of compartments in an interiorthereof, each of the electrode members being housed in one of thecompartments.
 10. The battery according to claim 9, wherein the batterycase includes a cover that seals the compartments.
 11. A method forassembling a battery including bus bars in a case made of resin, themethod comprising: electrically connecting plural electrode members eachhaving a positive electrode, a negative electrode, and an insulatingseparator arranged therebetween to the bus bars, such that each of thebus bars is electrically connected to two electrode members.
 12. Themethod according to claim 11, wherein the electrode members haveconnectors which project from the positive and negative electrodes andthe bus bars each have positive and negative terminals formed with holestherein into which the connectors of the electrode members are inserted.13. The method according to claim 12, wherein each of the bus barsincludes a voltage detection terminal that is electrically connectedbetween the terminals thereof, and is exposed to an exterior of thecase.
 14. The method according to claim 13, wherein the case includes apartition plate to form a plurality of compartments in an interiorthereof, each of the electrode members being housed in one of thecompartments.
 15. The battery according to claim 14, wherein the caseincludes a cover that seals the compartments.
 16. A method forassembling a battery comprising: partitioning a case to have a pluralityof interior compartments; arranging plural electrode members in theinterior compartments, each of the electrode members having a positiveelectrode, a negative electrode, and an insulating separator arrangedtherebetween; electrically connecting the positive electrodes and thenegative electrodes of the electrode members to bus bars formed in thecase; and closing up the interior compartments in which the electrodemembers are arranged.
 17. The method according to claim 16, wherein theelectrode members have connectors which project from the positive andnegative electrodes and the bus bars each have a terminal formed withholes therein into which the connectors of the electrode members areinserted.
 18. The method according to claim 17, wherein each of the busbars includes a voltage detection terminal that is electricallyconnected between the terminals thereof, and is exposed to an exteriorof the case.
 19. The method according to claim 18, wherein the case ispartitioned by inserting a partition plate.
 20. The method according toclaim 16, wherein such each of the bus bars is electrically connected totwo electrode members.